Mazda RX-8 2009 Service Highlights page 299

Example: ABS HU/CM-related wiring harness open circuit (if DTC is output)
1. Verify the CAN system-related module DTCs and the failed module using the Mazda Modular Diagnostic
System (M-MDS).
Module
PCM
TCM
Instrument cluster
Module
ABS HU/CM
EPS
CONTROL
MODULE
M
K
CAN_H
1AM
BRANCH
PCM
A
1AI
CAN_L
2. The wiring harness between the ABS HU/CM and branch B, or the ABS HU/CM itself could have a malfunction
because the DTCs indicating a communication error between the ABS HU/CM and PCM/TCM, in addition to
"Fail" on the ABS HU/CM, are displayed even though communication between the PCM and TCM is normal.
End Of Sie
09-40–14
2009 Mazda RX-8 Service Highlights (3452–1U–08C)
CONTROL SYSTEM
Displayed DTC
U0121
U0121
U1900
TCM
1C
1G
CONNECTOR
C-07
BRANCH
B
O R
ABS HU/CU
FAIL
Probable malfunction location
ABS HU/CM communication error
ABS HU/CM communication error
CAN system communication error
CONNECTOR
C-09
BRANCH
C
3W
3X
KEYLESS
CONTROL
MODULE
Fail
#
: FRONT HARNESS
: DASHBOARD HARNESS
: REAR HARNESS
1J
INSTRUMENT
BRANCH
D
CLUSTER
1L
L K
DLC-2
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